Within production printing environments, large numbers of pages are printed by printing devices, many times around the clock. Unlike personal or workgroup printing devices, production printing devices typically receive the pages after the pages already have been rasterized. As such, a production printing device can immediately begin to print a received page, instead of having to first convert the page from a page description language (PDL) into a rasterized format. Therefore, no time is wasted by the production printing device processing a page to rasterized format; instead, the production printing device is substantially actually outputting printed pages at all times.
As such, within a production printing environment, the pages of a print job that are to be printed in a given printed-page number order have to be rasterized (i.e., converted from a PDL to a rasterized format) prior to being transmitted to a printing device for printing. Rasterization is referred to as raster-image processing (RIP) herein. Rasterization is the process of converting text and images described in a PDL into a matrix of pixels, such as a bitmap, for actual printing by a printing device. Various conversions may take place within RIP. For example, the mathematical coordinates of vector and outline fonts, as well as vector drawings, are converted into bitmaps. Existing bitmaps may further have to be scaled into different-sized bitmaps.
Although it stands to reason that the pages of a print job would ideally be rasterized in the printed-page number order in which the pages are to be printed by a printing device, this is often not the case. Some pages require more time to rasterize than other pages do, as a result of such pages having more complex graphics or other features that require a longer time to rasterize. As a result, if the pages of a print job were rasterized in their printed-page number order, in likelihood the production printing device would not be outputting printed pages at substantially at all times, but rather would be waiting at times for the rasterization of pages having complex graphics or other features to be finished.